Uses of biobased styrene

ABSTRACT

Disclosed herein various uses of styrene monomers derived from biobased material and containing modern carbon atoms, including in copolymers, in rubber compositions, in tire components, and to balance the viscoelastic properties of a rubber composition containing the styrene monomer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage of International ApplicationNumber PCT/US2013/069232 filed on Nov. 8, 2013, which claims priority toU.S. provisional application Ser. No. 61/724,611, filed Nov. 9, 2012,both of which are hereby incorporated by reference in their entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to various uses of styrene monomersderived from biobased material containing modern carbon atoms, includingin polymers or copolymers, in rubber compositions, in tire components,and to balance the viscoelastic properties of a rubber compositioncontaining the styrene monomer.

BACKGROUND

Styrene is a common raw material of rubbery copolymers, such asstyrene-butadiene copolymers (SBR), styrene-isoprene copolymers, andstyrene-isoprene-butadiene copolymers (SIBR). These rubbery copolymersare often used in vulcanizable rubber compositions suitable fordifferent components of tires, e.g., the tread, the bead, the sidewall,etc. Styrene raw materials used on an industrial scale are typicallyderived from petroleum-based hydrocarbons. Styrene is typically producedvia the alkylation of petroleum-derived benzene with petroleum-derivedethylene.

Petrochemical-based hydrocarbons are fossil fuels, which by theirnature, do not contain any “modern” carbon. Modern carbon, as definedherein, refers to the standard set forth in ASTM D6866. Generallyspeaking, under this standard, modern carbon contains the same ¹⁴Cactivity level (including the post-1950 correction) as the originaloxalic acid radiocarbon standard (SRM 4990b). ¹⁴C, also known ascarbon-14 or radiocarbon, is a radioactive isotope of carbon that occursnaturally and is found in plants and animals at approximately the sameconcentration found in the atmosphere. Due to radioactive decay, fossilfuels lack any measurable ¹⁴C activity, and, therefore, do not containany modern carbon. Newer organic materials, including the biobasedmaterials disclosed herein, will display ¹⁴C activity, and thereforewill contain modern carbon.

SUMMARY

Disclosed herein are various uses of styrene monomers derived frombiobased material and containing modern carbon atoms, including inpolymers or copolymers, in rubber compositions, in tire components, andto balance the viscoelastic properties of a rubber compositioncontaining the styrene monomers.

Disclosed herein is a polymer or copolymer based upon styrene monomerand optionally including conjugated-diene monomer, wherein the polymeror copolymer comprises at least 50 weight percent of the styrenemonomer, and the styrene monomer contains 50-100% modern carbon atoms.

Also disclosed herein is a method for balancing the viscoelasticproperties of a rubber composition comprising incorporation of at least50 phr of a polymer or copolymer based upon styrene monomer andoptionally including conjugated-diene monomer, wherein the polymer orcopolymer comprises at least 50 weight percent of the styrene monomer,and the styrene monomer contains 50-100% modern carbon atoms.

Other aspects of the present disclosure will be apparent from thedescription that follows.

DETAILED DESCRIPTION

Disclosed herein are polymers and copolymers based upon styrene monomersderived from biobased material containing modern carbon atoms, rubbercompositions containing such polymers or copolymers, and methods forbalancing the viscoelastic properties of a rubber composition byincorporating the polymers or copolymer. Also disclosed are tirecomponents containing the rubber compositions disclosed herein.

Disclosed herein is a polymer or copolymer based upon styrene monomerand optionally including conjugated-diene monomer, wherein the polymeror copolymer comprises at least 50 weight percent of the styrenemonomer, and the styrene monomer contains 50-100% modern carbon atoms.

Also disclosed herein is a method for balancing the viscoelasticproperties of a rubber composition comprising incorporation of at least50 phr of a polymer or copolymer based upon styrene monomer andoptionally including conjugated-diene monomer, wherein the polymer orcopolymer comprises at least 50 weight percent of the styrene monomer,and the styrene monomer contains 50-100% modern carbon atoms.

Biobased Styrene Monomers

Styrene monomers serve as a raw material for many different rubberycopolymers. As mentioned above, styrene used on an industrial scale istypically derived from petroleum, which is a non-renewable fossil fuel.The styrene disclosed herein, in contrast, is at least partially derivedfrom a biobased material. The term “biobased,” unless otherwiseindicated herein, refers to organic materials derived from biologicsources, i.e., living sources. Biobased materials are typicallyrenewable in the sense that they are able to biologically or naturallyreplenish over time. Non-limiting broad types of biobased materialincludes animal material, plant material, and combinations thereof.

Biobased materials contain modern carbon as defined by ASTM D6866. Underthis standard, modern carbon has the same ¹⁴C activity level (includingthe post-1950 correction, i.e., 0.95 times the concentration of the ¹⁴C)as the original oxalic acid radiocarbon standard (SRM 4990b). Thus, anentire source of carbon that has the same activity level, after thepost-1950 correction, as the original oxalic acid radiocarbon standardhas 100% modern carbon atoms (the % modern carbon atoms may also bereferred to as percent modern carbon or pMC). Conversely, any carbonsource that lacks any ¹⁴C activity does not have any modern carbonatoms. A carbon source that lacks ¹⁴C activity is a fossil carbonsource.

In accordance with one or more embodiments, a styrene monomer derivedfrom a biobased styrene source material is disclosed. The styrenemonomer comprises 50% to 100% modern carbon atoms. In certainembodiments, the styrene monomer contains 75% to 100%, and in otherembodiments 100% modern carbon atoms.

In accordance with one or more embodiments, the styrene monomer derivedfrom a biobased styrene source material, and containing the percentagesof modern carbon atoms as discussed above, meets at least one of thefollowing: (a) contains at least 0.5% by weight styrene-derivedimpurities, preferably at least 1% by weight styrene-derived impurities,and/or (b) is produced from cinnamic acid. In certain exemplaryembodiments, the styrene-derived impurities comprise styrene dimers,styrene trimers, and hydroxy-substituted styrene compounds. Morespecific examples of the styrene-derived impurities includeethylbenzene, 1-phenyl-ethanol, styrene dimer, styrene trimer,bis(1-phenyl-ethyl)ether, and 1,3-diphenyl-3-hydroxy-1-butene. Thus, incertain exemplary embodiments, the styrene-derived impurities compriseone or more of: ethylbenzene, 1-phenyl-ethanol, styrene dimer, styrenetrimer, bis(1-phenyl-ethyl)ether, and 1,3-diphenyl-3-hydroxy-1-butene.

Suitable sources of biobased styrene source materials include cinnamicacid, derivatives of cinnamic acid, syngas (i.e., biobased syngas suchas syngas from biomass), methane (i.e., biobased methane such as methanefrom biomass), ethanol, butanol, and combinations thereof. In accordancewith the embodiments disclosed herein, each of these biobased sourcematerials comprise organic materials derived from biologic sources. Forexample, cinnamic acid can be obtained from cinnamon oil; resinousexudates from balsam trees, e.g., storax; fat extracts from shea trees,e.g., shea butter; and deamination of L-phenylalanine made from biomass.Biobased derivatives of cinnamic acid, such as hydrocinnamic acid, are,as their name implies, derived from biobased cinnamic acid. Biobasedhydrocinnamic acid can be obtained by hydrogenating biobased cinnamicacid. Biobased syngas, which typically contains hydrogen, carbonmonoxide, and carbon dioxide, can be obtained through the gasificationof biomass. Biobased methane can be produced by the catalytic conversionof a biobased syngas. Biobased butanol and biobased ethanol, can beproduced by the fermentation of biomass. For example, each of butanoland ethanol can be produced by the acetone-butanol-ethanol method offermentation, which is the bacterial fermentation of carbohydrates suchas starch in the absence of oxygen. Biobased ethanol can also beproduced from yeast fermentation of carbohydrates such as cellulose.

In accordance with one or more embodiments, styrene is produced from atleast one of biobased cinnamic acid or biobased derivatives of cinnamicacid in the following manner. The biobased cinnamic acid is firsthydrogenated to produce a biobased hydrocinnamic acid. Alternatively,this process may start with a biobased hydrocinnamic acid sourcematerial. In either instance, the biobased hydrocinnamic acid is thendecarbonylated using palladium, rhodium, iridium, platinum, or nickelcatalysts in the presence of an organic anhydride, such as pivalicanhydride, maleic anhydride, succinic anhydride, anhydrides of fattyacids containing from 4 to 36 carbon atoms, and the like; and aphosphine ligand, such as triphenylphosphine,bis(2-diphenylphosphinophenyl)ether (DPEphos),9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (Xantphos),1,3-bis(diphenylphosphino)propane, 1,3-bis(diphenylphosphino)ethane, andthe like; to produce the styrene monomer. Nonlimiting specific examplesof the catalysts include PdCl₂, PdI₂, PdBr₂, and the like. Nonlimitingspecific examples of the anhydrides of fatty acids containing from 4 to36 carbon atoms include decanoic anhydride, dodecanoic anhydride, andthe like. A specific example of this process is described in theExamples of the present disclosure. In this specific example, a biobasedhydrocinnamic acid, pivalic anhydride, a palladium catalyst, i.e.,PdCl₂, and a phosphine ligand, i.e., triphenylphosphine, are loaded intothe reaction vessel in an inert atmosphere. The vessel is heated, duringwhich styrene, carbon monoxide, and pivalic acid are produced via themetal-catalyzed decarbonylation of the hydrocinnamic acid. In one ormore embodiments, the styrene produced by this process can be isolatedfrom any residual reactants, catalyst residue, and other reactionproducts by any means known in the art, such as extraction, filtration,chromatography, and combinations thereof. In certain embodiments, it isadvantageous to not separate the resulting carboxylic acids orneutralized carboxylic acids from the products of this process. In otherwords, the styrene monomer is isolated along with any resultingcarboxylic acids or neutralized carboxylic acids. Thus, in certainembodiments, the isolation of the styrene shown in the Examples can bealtered to retain both the biobased styrene and the carboxylic acidresidue or the salt of carboxylic acid residue, e.g., any carboxylicacid residue neutralized with a suitable base, such as sodium hydroxide,present in the mixture. The carboxylic acid or carboxylic acid saltpresent in the mixture may be useful as an emulsifying agent when thestyrene monomer is used in emulsion polymerization reactions, which arediscussed in greater detail below.

Alternatively, the biobased cinnamic acid itself can be decarboxylatedto form the styrene monomer. This can be done using a decarboxylaseenzyme.

In accordance with one or more embodiments, styrene is produced from atleast one of a biobased source material that include syngas, methane,ethanol, and butanol in the following manner. Styrene is also known asvinyl benzene, which may be produced by the dehydrogenation ofethylbenzene. The at least one of biobased syngas, biobased methane,biobased ethanol, biobased butanol, and combinations thereof can be usedto form the intermediate constituent components used to formethylbenzene, which in turn is dehydrogenated to form styrene. Forexample, ethylbenzene can be formed by the alkylation of ethylene andbenzene. A biobased ethylene is obtained by dehydration of biobasedethanol. Biobased benzene is formed by the aromatization of biobasedmethane, which as discussed above, can be derived from the catalyticconversion of biobased syngas. Alternatively, benzene can be formed bythe aromatization of butane, which can be formed by the dehydration ofbiobased butanol. In accordance with the styrene disclosed herein, anyor all of the source materials used in this manner to form styrene,i.e., used to form the intermediate constituent components of styrene,are biobased. In other words, at least one of syngas, methane, ethanol,and butanol used to form the styrene disclosed herein is biobased.

Polymers and Copolymers Produced from the Biobased Styrene Monomer

In accordance with one or more embodiments, a polymer or copolymer isproduced that is based upon the biobased styrene monomers discussedherein. It should be understood that the styrene monomers upon which thepolymer or copolymer is based, are those biobased styrene monomerdiscussed above. The polymer or copolymer is produced from styrenemonomers containing from 50% to 100% modern carbon atoms, and in certainembodiments, from 75% to 100% modern carbon atoms, and in otherembodiments 100% modern carbon atoms. The resulting polymer or copolymeris polymerized from the styrene monomer described herein and optionallya conjugated-diene monomer.

In accordance with certain embodiments, the at least one other monomer(in addition to the styrene monomer) is a conjugated diene-containingmonomer and the resulting copolymer produced is a conjugateddiene-containing copolymer. Non-limiting examples of conjugateddiene-containing monomers suitable for use in the disclosed copolymersinclude 1,3-butadiene, isoprene, 1,3-pentadiene,2,3-dimethyl-1,3-butadiene, 1,3-hexadiene, 2-methyl-1,3-pentadiene,3,4-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene,3-butyl-1,3-octadiene, phenyl-1,3-butadiene, and combinations thereof.

In accordance with one or more embodiments, the polymer or copolymerproduced using the styrene derived from the biobased source material ispolystyrene, styrene-butadiene copolymer, styrene-isoprene copolymer, orstyrene-isoprene-butadiene. A styrene-butadiene copolymer is produced bypolymerizing the styrene monomer disclosed herein in the presence of a1,3-butadiene monomer. The polymer or copolymer can be produced usinganionic polymerization or emulsion polymerization. The anionicpolymerization generally takes place in solution. The anionic andemulsion polymerization techniques are discussed in greater detailbelow. The percent modern carbon content of the resulting polymer orcopolymer will primarily depend on the percent modern carbon content ofthe respective styrene monomer and 1,3-butadiene monomer, if any, usedin the polymerization. Generally, the higher the percent modern carboncontent for the monomer(s), the higher the percent modern carbon contentfor the overall copolymer.

In one or more embodiments, when only the styrene monomer is utilized orcontains modern carbon atoms, the polymer or copolymer contains 5% to60% modern carbon atoms, and in certain embodiments, from 20% to 50%modern carbon atoms, and in other embodiments from 25% to 40% moderncarbon atoms.

In other embodiments, a conjugated diene monomer such as 1,3-butadieneis used to produce the copolymer, and that conjugated diene monomer isderived from a biobased source material and therefore itself containsmodern carbon atoms. In such embodiments, the conjugated-diene monomeritself contains from 25% to 100% modern carbon atoms, including incertain embodiments from 50% to 100% modern carbon atoms, and in otherembodiments from 75% to 100% modern carbon atoms. When both the styrenemonomer and the conjugated diene monomers contain modern carbon atoms inaccordance with the present embodiment, the resulting copolymer containsfrom 25% to 100% modern carbon atoms, including in certain embodimentsfrom 50% to 99.99% modern carbon atoms, and in other embodiments from75% to 99.99% modern carbon atoms. A non-limiting example of a suitablebiobased butadiene source material is biobased ethanol. The process forconverting the biobased ethanol to biobased butadiene is well known andcan be done in accordance with the process described in Toussaint, W. J.et al., “Production of Butadiene from Alcohol,” Ind. Eng. Chem., 1947,39 (2), pp. 120-125, the contents of which are incorporated herein byreference.

As mentioned above, the percent modern carbon content of the resultingpolymer or copolymer depends on the modern carbon content of theconstituent monomer(s), i.e., the styrene monomer and anyconjugated-diene monomer utilized, as well as certain materials usedduring the polymerization reaction, such as catalysts, solvents,initiating agents, terminating agents, etc., that may add one or morecarbons to the resulting copolymer. It is possible to obtain a copolymerhaving 100% modern carbon atoms if all monomer(s), i.e., the styrenemonomer and any conjugated-diene monomer utilized, contain 100% moderncarbon atoms and no substitution reactions with non-modern carbon atomsoccur during polymerization, e.g., via an initiator or a quenchingagent. This is possible using a electron transfer initiators, such aslithium naphthalenide, in anionic polymerization reactions such as thosedescribed in Quirk, R. P. et al., ANIONIC POLYMERIZATION: PRINCIPLES ANDPRACTICAL APPLICATIONS, Marcel Dekker, Inc., 1996, pp. 104-108, which isincorporated herein by reference. Using other types of initiators mayresult in 100% or slightly less than 100%, e.g., 99.99%, of moderncarbon atoms in the resulting polymer or copolymer.

In accordance with one or more of the preceding embodiments, astyrene-butadiene copolymer is produced that contains 10% to 60% ofbound styrene by total weight of the copolymer, including in certainembodiments from 15% to 50% of bound styrene, and in other embodiments,from 20% to 40% of bound styrene.

The styrene-butadiene copolymers disclosed herein may also be describedin terms of the amount of microblock styrene structure of the copolymer.The term “microblock” as used herein refers to blocks within a copolymerthat contains a continuous run of 3 to 10 styrene units, i.e., 3 to 10styrene units in a row without intervening butadiene monomers. Inaccordance with one or more embodiments, the styrene-butadiene monomersdisclosed herein may contain up to 60% by weight of the total styrenepresent in the copolymer in microblock form, i.e., 0 to 60% of thestyrene in microblock form, and in certain other embodiments, from 10 to40% or from 20% to 30% of the styrene in microblock form.

In accordance with one or more embodiments, the resulting conjugateddiene-containing copolymer produced using the styrene derived from thebiobased source material is a styrene-isoprene copolymer. Thestyrene-isoprene copolymer is produced by polymerizing the styrenemonomer disclosed herein in the presence of an isoprene monomer. Thiscopolymer can be produced using anionic polymerization or emulsionpolymerization according to the anionic and emulsion polymerizationtechniques discussed in greater detail below.

In certain embodiments, the isoprene monomer used to produce thestyrene-isoprene copolymer is derived from a biobased isoprene sourcematerial and therefore contains modern carbon atoms. In suchembodiments, the isoprene monomer itself contains from 25% to 100%modern carbon atoms, including in certain embodiments from 50% to 100%modern carbon atoms, and in other embodiments from 75% to 100% moderncarbon atoms. When both the styrene monomer and the isoprene monomercontain modern carbon atoms in accordance with the present embodiment,the resulting styrene isoprene copolymer contains from 25% to 100%modern carbon atoms, including in certain embodiments from 50% to 99.99%modern carbon atoms, and in other embodiments from 75% to 99.99% moderncarbon atoms. A non-limiting example of a suitable biobased isoprenesource material includes biobased butanols, pentanols, and combinations,thereof, which can be obtained by thermochemical or fermentationprocessing of biomass. The process for converting these biobasedalcohols to isoprene is described in U.S. Patent Application PublicationNo. 2010/0216958, the contents of which are incorporated herein byreference. Alternatively, examples of a biobased isoprene source includecarbohydrates, glycerol, glycerine, dihydroxyacetone, single-carbonsources, animal fat, animal oils, fatty acids, lipids, phospholipids,glycerolipids, monoglycerides, diglycerides, triglycerides,polypeptides, yeast extracts, and combinations thereof. The process forconverting these biobased sources to isoprene is described in U.S.Patent Application Publication No. 2011/0237769, the contents of whichare incorporated herein by reference.

In accordance with one or more embodiments, the resulting conjugateddiene-containing copolymer produced using the styrene derived from thebiobased source material is a block copolymer such asstyrene-butadiene-styrene (SBS) or styrene-isoprene-styrene (SIS). Blockcopolymers such as SBS and SIS are generally made by anionicpolymerization processes wherein the first S block is made bypolymerizing styrene monomer alone (i.e., in the absence of any1,3-butadiene or isoprene) to completion, then adding 1,3-butadienemonomer or isoprene monomer and polymerizing to form the second B or Iblock, and finally adding another charge of styrene monomer to form thefinal S block. Block copolymers such as SBS and SIS contain all oressentially all of their styrene content in block form. In other words,such block copolymers contain either no or very minimal amounts ofstyrene monomers next to a butadiene or isoprene monomer other than thestyrene monomer at the end of the first block and at the beginning ofthe third block. The percent modern carbon content of the resultingblock copolymer will primarily depend on the percent modern carboncontent of the respective styrene and 1,3-butadiene or isoprene monomersused in the polymerization. Generally, the higher the percent moderncarbon content for each monomer, the higher the percent modern carboncontent for the overall copolymer.

In one or more embodiments, when only the styrene monomer containsmodern carbon atoms, the SBS or SIS block copolymer contains 5% to 60%modern carbon atoms, and in certain embodiments, from 20% to 50% moderncarbon atoms, and in other embodiments from 25% to 40% modern carbonatoms. In other embodiments the 1,3-butadiene or the isoprene used toproduce the block copolymer is also derived from a respective biobasedbutadiene or isoprene source material and therefore itself containsmodern carbon atoms. In such embodiments, the 1,3-butadiene monomer orisoprene monomer itself contains from 25% to 100% modern carbon atoms,including in certain embodiments from 50% to 100% modern carbon atoms,and in other embodiments from 75% to 100% modern carbon atoms. When boththe styrene monomer and either the 1,3-butadiene or the isoprene monomercontain modern carbon atoms in accordance with the present embodiment,the resulting block copolymer contains from 25% to 100% modern carbonatoms, including in certain embodiments from 50% to 99.99% modern carbonatoms, and in other embodiments from 75% to 99.99% modern carbon atoms.

In accordance with one or more embodiments, the resulting conjugateddiene-containing copolymer produced using the styrene derived from thebiobased source material is a styrene-isoprene-butadiene copolymer. Thestyrene-isoprene-butadiene copolymer is produced by polymerizing thestyrene monomer disclosed herein in the presence of an isoprene monomerand a 1,3-butadiene monomer. This copolymer can be produced usinganionic polymerization or emulsion polymerization techniques that arediscussed in greater detail below. As is the case for the copolymersdiscussed above, the percent modern carbon content of the resultingstyrene-isoprene-butadiene copolymer will primarily depend on thepercent modern carbon content of the respective styrene, the isoprene,and the 1,3-butadiene monomers used in the polymerization. Generally,the higher the percent modern carbon content for each monomer, thehigher the percent modern carbon content for the overall copolymer.

In one or more embodiments, when only the styrene monomer containsmodern carbon atoms, the styrene-isoprene-butadiene copolymer contains5% to 60% modern carbon atoms, and in certain embodiments, from 20% to50% modern carbon atoms, and in other embodiments from 25% to 40% moderncarbon atoms.

In other embodiments, at least one of the isoprene monomer and the1,3-butadiene monomer used to produce the styrene-isoprene-butadienecopolymer is derived from a biobased source material and thereforecontains modern carbon atoms. Examples of suitable biobased sourcematerials for isoprene and 1,3-butadiene include, but are not limitedto, those biobased source materials for isoprene and 1,3-butadienedisclosed herein. In such embodiments, the isoprene monomer itself maycontain from 25% to 100% modern carbon atoms, including in certainembodiments from 50% to 100% modern carbon atoms, and in otherembodiments from 75% to 100% modern carbon atoms. In addition, the1,3-butadiene monomer itself may contain from 25% to 100% modern carbonatoms, including in certain embodiments from 50% to 100% modern carbonatoms, and in other embodiments from 75% to 100% modern carbon atoms.When the styrene monomer, the isoprene monomer, and the 1,3-butadienemonomer all contain modern carbon atoms in accordance with the presentembodiment, the resulting styrene butadiene copolymer contains from 25%to 100% modern carbon atoms, including in certain embodiments from 50%to 99.99% modern carbon atoms, and in other embodiments from 75% to99.99% modern carbon atoms.

In accordance with one or more of the preceding embodiments, thestyrene-isoprene-butadiene copolymer contains 10% to 60% of boundstyrene by total weight of the copolymer, including in certainembodiments from 15% to 50% of bound styrene, and in other embodiments,from 20% to 40% of bound styrene.

The styrene-isoprene-butadiene copolymers disclosed herein may also bedescribed in terms of the amount of microblock styrene structure of thecopolymer. In accordance with one or more embodiments, thestyrene-isoprene-butadiene monomers disclosed herein may contain up to60% by weight of the total styrene present in the copolymer inmicroblock form, i.e., 0 to 60% of the styrene in microblock form, andin certain other embodiments, from 10 to 40% or from 20% to 30% of thestyrene in microblock form.

In one or more embodiments, the polymer or copolymer resulting from thepolymerization of the biobased styrene monomer and the optionalconjugated-diene monomer is functionalized. The polymer or copolymer isfunctionalized at one or more of the polymer head, the polymer tail, andthe polymer backbone (e.g., a functionalized side chain).

In certain embodiments where the polymer or copolymer is functionalized,the functionalization is added by the use of a functional initiators.Functional initiators are typically an organolithium compounds thatadditionally include other functionality, often one or more nitrogenatoms (e.g., substituted aldimines, ketimines, secondary amines, etc.)optionally pre-reacted with a compound such as diisopropenyl benzene.Many functional initiators are known in the art. Exemplary ones aredisclosed in U.S. Pat. Nos. 5,153,159, 5,332,810, 5,329,005, 5,578,542,5,393,721, 5,698,464, 5,491,230, 5,521,309, 5,496,940, 5,567,815,5,574,109, 5,786,441, 7,153,919, 7,868,110 and U.S. Patent ApplicationPublication No. 2011-0112263, which are incorporated herein byreference.

In one or more embodiments, the functional initiator includes alithiated thioacetal such as a lithiated dithiane. Lithiated thioacetalsare known and include those described in U.S. Pat. Nos. 7,153,919,7,319,123, 7,462,677, and 7,612,144, which are incorporated herein byreference.

In one or more embodiments, the thioacetal initiators employed can bedefined by the formula:

where each R⁶ independently includes hydrogen or a monovalent organicgroup, R⁰ includes a monovalent organic group, z is an integer from 1 toabout 8, and ω includes sulfur, oxygen, or tertiary amino (NR, where Ris an organic group).

In one or more embodiments, the functional initiators may be defined bythe formula:

where R⁰ includes a monovalent organic group.

Specific examples of functional initiators include2-lithio-2-phenyl-1,3-dithiane,2-lithio-2-(4-dimethylaminophenyl)-1,3-dithiane, and2-lithio-2-(4-dibutylaminophenyl)-1,3-dithiane,2-lithio-[4-(4-methylpiperazino)]phenyl-1,3-dithiane,2-lithio-[2-(4-methylpiperazino)]phenyl-1,3-dithiane,2-lithio-[2-morpholino]phenyl-1,3-dithiane,2-lithio-[4-morpholin-4-yl]phenyl-1,3-dithiane,2-lithio-[2-morpholin-4-yl-pyridine-3]-1,3-dithiane,2-lithio-[6-morpholin-4-pyridino-3]-1,3-dithiane,2-lithio-[4-methyl-3,4-dihydro-2H-1,4-benzoxazine-7]-1,3-dithiane, andmixtures thereof.

Polymerization of the Polymers or Copolymers

In accordance with one or more embodiments, the polymer or copolymerdisclosed herein are produced using anionic polymerization. Anionicpolymerization is a form of addition polymerization that occurs in threestages, chain initiation, chain propagation, and chain termination. Inparticular, anionically formed polymer or copolymer may be formed byreacting anionic initiators with certain unsaturated monomers, namelythe styrene monomer disclosed herein and optionally the conjugated-dienemonomer, to propagate a polymeric structure. Throughout formation andpropagation of the polymer, the polymeric structure may be understood as“living,” i.e., reactive. A new batch of monomer subsequently added tothe reaction can add to the living ends of the existing chains andincrease the degree of polymerization.

Anionic polymerizations are typically conducted as solutionpolymerizations, i.e., in a solvent, but may also be carried out asvapor phase polymerization or bulk polymerization. Suitable solvents forthe anionic polymerization include a polar solvent, such astetrahydrofuran (THF), or a non-polar hydrocarbon solvent, such as thevarious cyclic and acyclic hexanes (e.g., cyclohexane and hexane),heptanes, octanes, pentanes, their alkylated derivatives, and mixturesthereof, as well as benzene.

In certain embodiments where the polymer or copolymer is prepared by thesolution polymerization, the total concentration of the monomers in thesolution is preferably within a range of 5% to 50% by mass, morepreferably 10% to 30% by mass. The content of styrene monomer in themixture is preferably within a range of 3% to 50% by mass, morepreferably 4% to 45% by mass. Also, the polymerization system is notparticularly limited and may be a batch system or a continuous system.

The polymerization temperature in the anionic polymerization ispreferably within a range of 0° C. to 150° C., more preferably 20° C. to130° C. Also, such a polymerization may be carried out under agenerating pressure, but it is preferable to be usually conducted undera pressure enough to keep the monomers used at substantially a liquidphase. When the polymerization reaction is carried out under a pressurehigher than the generating pressure, the reaction system is preferableto be pressurized with an inert gas. Moreover, the starting materialsused in the polymerization such as monomers, polymerization initiator,solvent and the like are preferable to be used after the reactionobstructing substances such as water, oxygen, carbon dioxide, protoniccompound and the like are previously removed.

Suitable anionic initiators include organometallic compounds, such asorganic alkali metal compounds. Specific examples of suitable organicalkali metal compounds include, but are not limited to, organolithium,organomagnesium, organosodium, organopotassium, tri-organotin-lithiumcompounds, lithium naphthalenide, sodium naphthalenide, and combinationsthereof. Examples of suitable organolithium compounds include, but arenot limited to, n-butyl lithium, sec-butyl lithium, t-butyl lithium, andthe like.

The amount of anionic initiator required to effect the desiredpolymerization can be varied over a wide range depending upon a numberof factors, such as the desired polymer or copolymer molecular weightand the desired physical properties for the polymer or copolymerproduced. In general, the amount of initiator utilized can vary from aslittle as 0.1 millimoles (mM) of lithium per 100 grams of monomers up to100 mM of lithium per 100 grams of monomers, depending upon the desiredcopolymer molecular weight.

In order to promote randomization in copolymerization and to controlvinyl content, a polar coordinator may be added to the polymerizationingredients. The amount of polar coordinator used depends on the amountof vinyl desired, the level of styrene employed and the temperature ofthe polymerization, as well as the nature of the specific polarcoordinator (modifier) employed. Suitable polar coordinator include forexample, ethers, or amines to provide the desired microstructure andrandomization of the monomer units.

Types of compounds useful as polar coordinators include those having anoxygen or nitrogen heteroatom and a non-bonded pair of electrons.Suitable examples include, but are not limited to, dialkyl ethers ofmono and oligo alkylene glycols; “crown” ethers; tertiary amines such astetramethylethylene diamine (TMEDA); linear THF oligomers; and the like.Specific examples suitable polar coordinators include, but are notlimited to, tetrahydrofuran (THF), linear and cyclic oligomeric oxolanylalkanes such as 2,2-bis(2′-tetrahydrofuryl) propane, dipiperidyl ethane,dipiperidyl methane, hexamethylphosphoramide, N—N′-dimethylpiperazine,diazabicyclooctane, dimethyl ether, diethyl ether, tributylamine and thelike. Linear and cyclic oligomeric oxolanyl alkane coordinators aredescribed in U.S. Pat. No. 4,429,091, incorporated herein by reference.

To terminate the polymerization, and, thus, control the polymer orcopolymer molecular weight, a quenching agent, coupling agent, orlinking agent may be employed, all of these agents being collectivelyreferred to herein as “terminating reagents.” Useful terminatingreagents include active hydrogen compounds such as water or alcohol.Certain of these reagents may provide the resulting polymer withfunctionality. That is, the polymers initiated according to the presentdisclosure, may carry the functional head group as discussedhereinabove, and may also carry a second functional group as a result ofthe terminating reagents, i.e., quenching agents, coupling agents, andlinking agents used in the polymerization reaction.

Suitable functional terminating reagents are those disclosed in U.S.Pat. Nos. 5,502,131, 5,496,940 and 4,616,069, the contents of which areincorporated herein by reference, and include, but are not limited to,tin tetrachloride, (R)₃SnCl, (R)₂SnCl₂, RSnCl₃, carbodiimides, N-cyclicamides, N,N′ disubstituted cyclic ureas, cyclic amides, cyclic ureas,isocyanates, Schiff bases, 4,4′-bis(diethylamino) benzophenone, alkylthiothiazolines, carbon dioxide and the like. Other terminating reagentsinclude the alkoxy silanes Si(OR)₄, RSi(OR)₃, R₂Si(OR)₂ cyclic siloxanesand mixtures thereof. The organic moiety R is selected from the groupconsisting of alkyls having from 1 to about 20 carbon atoms, cycloalkylshaving from about 3 to about 20 carbon atoms, aryls having from about 6to about 20 carbon atoms and aralkyls having from about 7 to about 20carbon atoms. Typical alkyls include n-butyl, s-butyl, methyl, ethyl,isopropyl and the like. The cycloalkyls include cyclohexyl, menthyl andthe like. The aryl and the aralkyl groups include phenyl, benzyl and thelike. Preferred endcapping agents are tin tetrachloride, tributyl tinchloride, dibutyl tin dichloride, tetraethylorthosilicate and1,3-dimethyl-2-imidazolidinone (DMI).

While terminating to provide a functional group on the terminal end ofthe polymer is preferred, it is further preferred to terminate by acoupling reaction, with for example, tin tetrachloride or other couplingagent such as silicon tetrachloride (SiCl₄), esters, and the like.

The amount of terminating agent required to effect the desiredtermination of the polymerization can be varied over a wide rangedepending upon a number of factors, such as the desired polymer orcopolymer molecular weight and the desired physical properties for thepolymer or copolymer produced. In general, the amount of terminatingreagent utilized can vary from a molar ratio of 0.1:5 to 0.5:1.5 to0.8:1.2 (terminating reagent:Li).

Anionically polymerized living polymers can be prepared by either batch,semi-batch or continuous methods. A batch polymerization is begun bycharging a blend of the styrene monomer and at least one other monomerand solvent to a suitable reaction vessel, followed by the addition ofthe polar coordinator (if employed) and an initiator compound. Thereactants are heated to a temperature of from about 20° C. to about 130°C. and the polymerization is allowed to proceed for from about 0.1 toabout 24 hours. This reaction produces a reactive polymer having areactive or living end. Preferably, at least about 30% of the polymermolecules contain a living end. More preferably, at least about 50% ofthe polymer molecules contain a living end. Even more preferably, atleast about 80% contain a living end.

A continuous polymerization is begun by charging styrene monomer and atoptionally a conjugated-diene monomer, initiator, and solvent at thesame time in a suitable reaction vessel. Thereafter, a continuousprocedure is followed that removes the product after a suitableresidence time and replenishes reactants.

In a semi-batch polymerization the reaction medium and initiator areadded to a reaction vessel, and the styrene monomer and at least oneother monomer are continuously added over time at a rate dependent ontemperature, monomer/initiator/modifier concentrations, etc. Unlike acontinuous polymerization, the product is not continuously removed fromthe reactor. The resulting polymer from each of the batch, continuous,and semi-batch process is a polymer cement.

Anionic polymerization is further described in George Odian, PRINCIPLESOF POLYMERIZATION, Wiley Intersciences, Inc., 3^(rd) Ed. (1991), Ch. 5,which is incorporated herein by reference.

After formation of the polymer/copolymer cement, a processing aid(s) andother optional additives, such as oil, can be added to the polymercement. The polymer or copolymer and other optional ingredients are thenisolated from the solvent and preferably dried. Conventional proceduresfor desolventization and drying may be employed. In one embodiment, thepolymer or copolymer is isolated from the solvent by steamdesolventization or hot water coagulation of the solvent followed byfiltration. Residual solvent can be removed by using conventional dryingtechniques such as oven drying or drum drying. Alternatively, the cementmay be directly drum dried.

In accordance with one or more embodiments, the polymers or copolymersdisclosed herein are produced using emulsion polymerization. Emulsionpolymerization is a form of free radical polymerization. In one or moreembodiments, a reaction vessel is charged with water, an emulsifyingagent, the styrene monomer, the at least one other monomer, and a freeradical initiator. The polymerization conversion may be controlled byadding the monomers in a step-wise manner, i.e., adding a portion of thetotal styrene monomer and the optional conjugated-diene monomer in afirst step, then after achieving a desired conversion, adding additionalportions of the styrene and at least one other monomers in subsequentsteps to obtain a higher conversion rate. The emulsion polymerizationreaction occurs from 0° C. to about 20° C., preferably from 0° C. to 10°C.

Examples of suitable free radical initiators include, but are notlimited to potassium persulfate, ammonium persulfate, benzoyl peroxide,hydrogen peroxide, di-t-butyl peroxide, dicumyl peroxide,2,4-dichlorobenzoyl peroxide, decanoyl peroxide, lauryl peroxide, cumenehydroperoxide, p-menthane hydroperoxide, t-butyl hydroperoxide, acetylacetone peroxides dicetyl peroxydicarbonate, t-butyl peroxyacetate,t-butyl peroxymaleic acid, t-butyl peroxybenzoate, acetyl cyclohexylsulfonyl peroxide, and the like; the various azo compounds such as2-t-butylazo-2-cyanopropane, dimethyl azodiisobutyrate,azodiisobutyronitrile, 2-t-butylazo-1-cyanocyclohexane,1-t-amylazo-1-cyanocyclohexane, and the like; the various alkylperketals, such as 2,2-bis-(t-butylperoxy)butane, ethyl3,3-bis(t-butylperoxy)butyrate, 1,1-di-(t-butylperoxy) cyclohexane, andthe like. These compounds are thermally unstable and decompose at amoderate rate to release free radicals. In certain embodiments, thecombination of potassium persulfate with a mercaptan such as dodecylmercaptan is commonly used to polymerize styrene-butadiene copolymers.The mercaptan generally acts as a chain transfer agent by reacting withone growing copolymer chain to terminate it and initiate growth ofanother chain. In certain embodiments, the mercaptan also acts as a freeradical initiator through reaction with the persulfate. This activity bythe mercaptan occurs at reactions taking place at higher temperatures.The amount of initiator employed will vary with the desired molecularweight of the copolymer being synthesized. Higher molecular weights areachieved by utilizing smaller quantities of the initiator and lowermolecular weights are attained by employing larger quantities of theinitiator.

Examples of suitable types emulsifying agents include, but are notlimited to, anionic, nonionic, and cationic surfactants. Moreparticularly, examples of emulsifying agents include various fatty acidsoaps such as sodium stearate, rosin acid soaps, sodium lauryl sulfate,alpha olefin sulfonate, and the like.

Rubber Compositions Containing the Polymers or Copolymers

In accordance with one or more embodiments, the polymers or copolymersdisclosed herein, are used in rubber compositions. As discussed in moredetail herein, the polymers or copolymers, and rubber compositionscontaining such polymers or copolymers of this disclosure areparticularly useful in tire components. These tire components can beprepared by using the polymers or copolymers of this invention alone ortogether with other rubbery polymers. Other rubbery polymers that may beused include natural and synthetic conjugated diene polymers orcopolymers. The synthetic conjugated diene polymers or copolymers aretypically derived from the polymerization of conjugated diene monomersas discussed above. These conjugated diene monomers may be copolymerizedwith other monomers such as vinyl aromatic monomers. Other rubberyconjugated diene polymers or copolymers may be derived from thepolymerization of ethylene together with one or more alpha-olefins andoptionally one or more diene monomers.

Examples of suitable rubbery polymers or copolymers that may be used incombination with the polymers or copolymers disclosed herein includenatural rubber, synthetic polyisoprene, polybutadiene,polyisobutylene-isoprene copolymers, neoprene, ethylene-propylenecopolymers, styrene-butadiene copolymers such as solutionstyrene-butadiene copolymers and emulsion styrene butadiene copolymers,styrene-isoprene copolymers, styrene-isoprene-butadiene copolymers,isoprene-butadiene copolymers, ethylene-propylene-diene copolymers,polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber,epichlorohydrin rubber, and mixtures thereof. These rubbery polymers orcopolymers can have varying macromolecular structures including linear,branched and star shaped structures. Preferred rubbery polymers orcopolymers include natural rubber, polyisoprene, styrene-butadienecopolymers, and butadiene rubbers.

The rubber compositions include reinforcing fillers such as inorganicand organic fillers. Examples of common organic fillers include carbonblack and starch. Examples of inorganic fillers include silica, aluminumhydroxide, magnesium hydroxide, clays (hydrated aluminum silicates),mica, and combinations thereof. Preferred fillers are carbon black,silica and combinations thereof.

The rubber compositions can be compounded with all forms of carbon blackalone, or in a mixture with silica. The carbon black can be present inamounts ranging from about 5 to about 200 phr, with 5 to about 80 phrbeing preferred. When both carbon black and silica are employed incombination as the reinforcing filler, they are often used in a carbonblack-silica ratio of about 10:1 to about 1:4. In certain embodiments,carbon black may be added in small amounts as an additive to providecoloring to the tire rather than for its filler functionality. In suchembodiments, the carbon black to silica ratio is much lower such asabout 1:80.

The carbon blacks can include any of the commonly available,commercially-produced carbon blacks, but those having a surface area(EMSA) of at least 20 m²/g and, more preferably, at least 35 m²/g up to200 m²/g or higher are preferred. Surface area values used in thisapplication are determined by ASTM D-1765 using thecetyltrimethyl-ammonium bromide (CTAB) technique. Among the usefulcarbon blacks are furnace black, channel blacks and lamp blacks. Morespecifically, examples of useful carbon blacks include super abrasionfurnace (SAF) blacks, high abrasion furnace (HAF) blacks, fast extrusionfurnace (FEF) blacks, fine furnace (FF) blacks, intermediate superabrasion furnace (ISAF) blacks, semi-reinforcing furnace (SRF) blacks,medium processing channel blacks, hard processing channel blacks andconducting channel blacks. Other carbon blacks which can be utilizedinclude acetylene blacks. Examples of exemplary carbon blacks includethose bearing ASTM designation (D-1765-82a) N-110, N-220, N-339, N-330,N-351, N-550, and N-660. In one or more embodiments, the carbon blackmay include oxidized carbon black. A mixture of two or more of the aboveblacks can be used in preparing the rubber compositions disclosedherein. The carbon blacks utilized in the preparation of the rubbercompositions disclosed herein can be in pelletized form or anunpelletized flocculent mass. Preferably, for more uniform mixing,unpelletized carbon black is preferred.

Examples of suitable silica reinforcing fillers include, but are notlimited to, precipitated amorphous silica, wet silica (hydrated silicicacid), dry silica (anhydrous silicic acid), fumed silica, calciumsilicate, and the like. Other suitable fillers include aluminumsilicate, magnesium silicate, and the like. Among these, precipitatedamorphous wet-process, hydrated silicas are preferred. These silicas areso-called precipitated because they are produced by a chemical reactionin water, from which they are precipitated as ultra-fine, sphericalparticles. These primary particles strongly associate into aggregates,which in turn combine less strongly into agglomerates. The surface area,as measured by the BET method gives the best measure of the reinforcingcharacter of different silicas. For silicas of interest for the presentdisclosure, the surface area should be about 32 m²/g to about 400 m²/g,with the range of about 100 m²/g to about 250 m²/g being preferred, andthe range of about 150 m²/g to about 220 m²/g being most preferred. ThepH of the silica filler is generally about 5.5 to about 7 or slightlyover, preferably about 5.5 to about 6.8.

Silica can be employed in the amount of about 5 to about 200 phr,preferably in an amount of about 5 to about 80 phr and, more preferably,in an amount of about 30 to about 80 phr. The useful upper range islimited by the high viscosity imparted by fillers of this type. Some ofthe commercially available silicas which can be used include, but arenot limited to, Hi-Sil™ 190, Hi-Sil™ 210, Hi-Sil™ 215, Hi-Sil™ 233,Hi-Sil™ 243, and the like, produced by PPG Industries (Pittsburgh, Pa.).A number of useful commercial grades of different silicas are alsoavailable from Degussa Corporation (e.g., VN2, VN3), Rhone Poulenc(e.g., Zeosil™ 1165 MP), and J. M. Huber Corporation.

The rubber compositions disclosed herein optionally include a silicacoupling agent when silica is used as a reinforcing filler. Examples ofsuitable silica coupling agents include, but are not limited to, amercaptosilane, a bis(trialkoxysilylorgano) polysulfide, a3-thiocyanatopropyl trimethoxysilane, or the like, or any of the silicacoupling agents that are known to those of ordinary skill in the rubbercompounding art. Exemplary mercaptosilanes include, but are not limitedto, 1-mercaptomethyltriethoxysilane, 2-mercaptoethyltriethoxysilane,3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyl-diethoxysilane,2-mercaptoethyltriproxysilane, 18-mercaptooctadecyldiethoxychlorosilane,and the like. Exemplary bis(trialkoxysilylorgano) polysulfide silicacoupling agents include, but are not limited to,bis(3-triethoxysilyl-propyl) tetrasulfide (TESPT), which is soldcommercially under the tradename Si69® by Degussa Inc., New York, N.Y.,and bis(3-triethoxysilylpropyl) disulfide (TESPD) or Si75®, availablefrom Degussa, or Silquest™ A1589, available from Crompton. The silicacoupling agent can be present in an amount of 0.01% to 20% by weightbased on the weight of the silica, preferably 0.1% to 15% by weight, andmore preferably 1% to 10%. Compounding involving silica fillers is alsodisclosed in U.S. Pat. Nos. 6,221,943, 6,342,552, 6,348,531, 5,916,961,6,252,007, 6,369,138, 5,872,176, 6,180,710, 5,866,650, 6,228,908 and6,313,210, the disclosures of which are incorporated by referenceherein.

The rubber compositions disclosed herein are compounded or blended byusing mixing equipment and procedures conventionally employed in theart, such as mixing the various vulcanizable polymer(s) with reinforcingfillers and commonly used additive materials such as, but not limitedto, curatives such as vulcanizing agents, vulcanizing accelerators,anti-scorch agents, vulcanizing inhibitors, and combinations thereof(for a general disclosure of suitable vulcanizing agents one can referto Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd ed., WileyInterscience, N.Y. 1982, Vol. 20, pp. 365-468, particularly“Vulcanization Agents and Auxiliary Materials” pp. 390-402); processingadditives, such as oils; resins, including tackifying resins;plasticizers; pigments; additional fillers; fatty acid; zinc oxide;waxes; antioxidants; antiozonants; peptizing agents; and the like. Asknown to those skilled in the art, the additives mentioned above areselected and commonly used in conventional amounts.

In one or more embodiments, a rubber composition is disclosedcomprising: from 5 to 100 phr of first copolymer, wherein the firstcopolymer comprises a styrene monomer derived from a biobased styrenesource material and at least one conjugated diene-containing monomer,wherein the styrene monomer contains 50% to 100% modern carbon atoms;from 0 to 95 phr of a second polymer or copolymer selected from thegroup consisting of polyisoprene, polybutadiene, emulsionstyrene-butadiene copolymer, solution styrene-butadiene copolymer,natural rubber, and combinations thereof; and from 5 to 200 phr of atleast one reinforcing filler. In certain embodiments, the firstcopolymer contains 100% modern carbon atoms, and any of thepolyisoprene, polybutadiene, emulsion styrene-butadiene copolymer, andsolution styrene-butadiene copolymer present in the second polymer orcopolymer is 100% modern carbon atoms. Furthermore, in accordance withcertain embodiments, the rubber composition may also include from 0 to75 phr, and preferably from 0 to 40 phr of processing oils/aids; from 0to 10 phr, and preferably from 0 to 5 phr of antidegradants; from 0 to 5phr, and preferably from 0 to 3 phr of stearic acid; from 0 to 10 phr,and preferably from 0 to 5 phr of zinc oxide; from 0 to 10 phr, andpreferably from 0 to 4 phr of a vulcanizing agent such as sulfur; from 0to 10 phr, and preferably from 0 to 5 phr of vulcanizing accelerators;and when silica is used, from 0.01% to 20% by weight of a silicacoupling agent based on the weight of the silica, preferably 0.1% to 15%by weight, and more preferably 1% to 10%.

In one or more embodiments, a tire component of this disclosurecomprises a rubber composition comprising: from 5 to 100 phr of firstpolymer or copolymer, wherein the first polymer or copolymer is basedupon a styrene monomer derived from a biobased styrene source materialand optionally at least one conjugated diene-containing monomer, whereinthe styrene monomer contains 50% to 100% modern carbon atoms; from 0 to95 phr of a second polymer or copolymer selected from the groupconsisting of polyisoprene, polybutadiene, emulsion styrene-butadienecopolymer, solution styrene-butadiene copolymer, natural rubber, andcombinations thereof; and from 5 to 200 phr of at least one reinforcingfiller. In certain embodiments, the first polymer or copolymer copolymercontains 100% modern carbon atoms, and any of the polyisoprene,polybutadiene, emulsion styrene-butadiene copolymer, and solutionstyrene-butadiene copolymer present in the second polymer or copolymeris 100% modern carbon atoms. Furthermore, in accordance with certainembodiments, the rubber composition may also include from 0 to 75 phr,and preferably from 0 to 40 phr of processing oils/aids; from 0 to 10phr, and preferably from 0 to 5 phr of antidegradants; from 0 to 5 phr,and preferably from 0 to 3 phr of stearic acid; from 0 to 10 phr, andpreferably from 0 to 5 phr of zinc oxide; from 0 to 10 phr, andpreferably from 0 to 4 phr of a vulcanizing agent such as sulfur; from 0to 10 phr, and preferably from 0 to 5 phr of vulcanizing accelerators;and when silica is used, from 0.01% to 20% by weight of a silicacoupling agent based on the weight of the silica, preferably 0.1% to 15%by weight, and more preferably 1% to 10%.

In addition, in certain of the preceding embodiments, the rubbercomposition of the present disclosure comprises at least a firststyrene-butadiene copolymer and a second styrene-butadiene copolymer,where each of the first and second styrene-butadiene copolymers ispolymerized from the bioderived styrene monomer, and where the percentbound styrene in the first styrene-butadiene copolymer is different thanthe percent bound styrene in the second styrene-butadiene copolymer. Inadditional embodiments, the rubber composition includes a third polymerselected from the group consisting of styrene-butadiene copolymer,polybutadiene, natural rubber, and polyisoprene.

In one or more embodiments, the rubber compositions disclosed herein areprepared by forming an initial masterbatch that includes the rubbercomponent, i.e., the polymer or copolymer disclosed herein along withany additional conjugated diene polymer or copolymer, and filler. In oneor more embodiments, where silica is employed as a filler (alone or incombination with other fillers), a coupling and/or shielding agent maybe added to the rubber formulation during mixing. This initialmasterbatch may be mixed at a starting temperature of from about 25° C.to about 125° C. with a discharge temperature of about 135° C. to about180° C. To prevent premature vulcanization (also known as scorch), thisinitial masterbatch may exclude vulcanizing agents. Once the initialmasterbatch is processed, the vulcanizing agents may be introduced andblended into the initial masterbatch at low temperatures in a final mixstage, which preferably does not initiate the vulcanization process.Optionally, additional mixing stages, sometimes called remills, can beemployed between the masterbatch mix stage and the final mix stage.Various ingredients including polymers and copolymers can be addedduring these remills.

Where the vulcanizable rubber compositions are employed in themanufacture of tires, these compositions can be processed into tirecomponents according to ordinary tire manufacturing techniques includingstandard rubber shaping, molding, and curing techniques. Any of thevarious rubber tire components can be fabricated including, but notlimited to, treads, sidewalls, belt skims, and carcass. Typically,vulcanization is effected by heating the vulcanizable composition in amold; e.g., it may be heated to about 140° C. to about 180° C. Cured orcrosslinked rubber compositions may be referred to as vulcanizates,which generally contain three-dimensional polymeric networks that arethermoset. The other ingredients, such as processing aides and fillers,may be evenly dispersed throughout the vulcanized network. Pneumatictires can be made as discussed in U.S. Pat. Nos. 5,866,171, 5,876,527,5,931,211, and 5,971,046, which are incorporated herein by reference.

Methods for Balancing Viscoelastic Properties of a Rubber Composition

As previously discussed, the present disclosure includes methods forbalancing the viscoelastic properties of a rubber composition comprisingincorporation of at least 50 phr of a polymer or copolymer as previouslydescribed, i.e., based upon styrene monomer and optionally includingconjugated-diene monomer, wherein the polymer or copolymer comprises atleast 50 weight percent of the styrene monomer, and the styrene monomercontains 50-100% modern carbon atoms.

In certain embodiments, the viscoelastic properties balanced are rollingresistance and wet traction, and the balancing comprises increasing wetfraction while maintaining or decreasing rolling resistance, as comparedto a control rubber composition that replaces the moderncarbon-containing polymer or copolymer with a polymer or copolymercontaining no modern carbon atoms. In other embodiments, the polymer orcopolymer containing a monomer with 50% to 100% modern carbon atoms ishead or tail functionalized, the viscoelastic properties balanced arerolling resistance and wet traction, and the balancing comprisesincreasing wet traction without a commensurate increase in rollingresistance, as compared to a control rubber composition that replacesthe modern carbon-containing polymer or copolymer with a polymer orcopolymer containing no modern carbon atoms.

EXEMPLARY EMBODIMENTS

In accordance with one or more embodiments, a styrene monomer derivedfrom a biobased styrene source material is disclosed. The styrenemonomer comprises 50% to 100% modern carbon atoms. In accordance withcertain embodiments, the biobased styrene source material includes atleast one of cinnamic acid, a derivative of cinnamic acid, syngas,methane, ethanol, butanol, and combinations thereof. In certain of thepreceding embodiments, the biobased styrene source material ishydrocinnamic acid. Furthermore, in certain of the precedingembodiments, the styrene monomer contains 100% modern carbon atoms. Acopolymer selected from the group consisting of styrene-butadiene,styrene-isoprene, and styrene-isoprene-butadiene can be produced fromthe styrene monomer of any of the preceding embodiments. In addition, incertain of the preceding embodiments, a tire component comprises theaforementioned copolymer.

In accordance with one or more embodiments, a polymer or copolymerproduced from a styrene monomer derived from a biobased styrene sourcematerial is disclosed. The styrene monomer contains 50% to 100% moderncarbon atoms. In accordance with certain of the preceding embodiments,the copolymer is selected from the group consisting ofstyrene-butadiene, styrene-isoprene, and styrene-isoprene-butadiene. Incertain of the preceding embodiments, the styrene monomer is derivedfrom at least one of cinnamic acid, a derivative of cinnamic acid,syngas, methane, ethanol, butanol, and combinations thereof.Furthermore, in certain of the preceding embodiments, the styrenemonomer contains 100% modern carbon atoms. In addition, in one or moreof the preceding embodiments, the copolymer is produced from at leastone conjugated diene-containing monomer. In accordance with certain ofthe preceding embodiments, the polymer or copolymer is produced from thestyrene monomer using anionic polymerization or emulsion polymerization.

Moreover, in certain of the preceding embodiments, the copolymer is astyrene-butadiene copolymer produced from the styrene monomer. Incertain embodiments, the styrene-butadiene copolymer contains 5% to 60%modern carbon atoms. In certain of the preceding embodiments, thestyrene-butadiene copolymer is produced from a 1,3-butadiene monomerderived from a biobased butadiene source material, and the butadienemonomer contains 25% to 100% modern carbon atoms. In accordance withcertain of the preceding embodiments, the styrene-butadiene copolymercontains 25% to 100% modern carbon atoms. In certain precedingembodiments, the styrene-butadiene copolymer contains 50% to 99.99%modern carbon atoms. Furthermore, in certain of the precedingembodiments, the styrene-butadiene copolymer contains 10% to 60% ofbound styrene by weight of the copolymer. In certain precedingembodiments, the styrene-butadiene copolymer contains 20% to 40% ofbound styrene by weight of the copolymer. Up to 60% by weight of thetotal styrene in the copolymer is present in microblock form inaccordance with certain of the preceding embodiments.

In addition, in certain of the preceding embodiments, the copolymer is astyrene-isoprene copolymer produced from the styrene monomer. Thestyrene-isoprene copolymer is produced from an isoprene monomer derivedfrom a biobased isoprene source material, and the isoprene monomercontains 25% to 100% modern carbon atoms.

In accordance with certain of the preceding embodiments, the copolymeris a styrene-isoprene-butadiene copolymer produced from the styrenemonomer. In certain of the preceding embodiments, thestyrene-isoprene-butadiene copolymer contains 5% to 60% modern carbonatoms. Furthermore, in certain of the preceding embodiments, thestyrene-isoprene-butadiene copolymer is produced from at least one of a1,3-butadiene monomer derived from a biobased butadiene source material,an isoprene monomer derived from a biobased isoprene source material,and combinations thereof. When the styrene-isoprene-butadiene copolymeris produced from a biobased butadiene source material, the 1,3-butadienemonomer contains 25% to 100% modern carbon atoms. In addition, when thestyrene-isoprene-butadiene copolymer is produced from a biobasedisoprene source material, the isoprene monomer contains 25% to 100%modern carbon atoms. In accordance with certain of the precedingembodiments, the styrene-isoprene-butadiene copolymer contains 25% to100% modern carbon atoms when the styrene-isoprene-butadiene copolymeris produced from both a biobased butadiene source material and abiobased isoprene source material. In certain of the precedingembodiments, the styrene-isoprene-butadiene copolymer contains 50% to99.99% modern carbon atoms when the styrene-isoprene-butadiene copolymeris produced from both a biobased butadiene source material and abiobased isoprene source material. In accordance with certain of thepreceding embodiments, the styrene-isoprene-butadiene copolymer contains10 to 60% of bound styrene by weight of the copolymer. Furthermore, incertain of the preceding embodiments, the styrene-isoprene-butadienecopolymer contains 20% to 40% of bound styrene by weight of thecopolymer.

In addition, in accordance with certain of the preceding embodiments,the polymer or copolymer is functionalized at one or more of the polymerhead, the polymer tail, and the polymer backbone. Moreover, inaccordance with certain of the preceding embodiments, a tire componentcomprises the aforementioned polymer or copolymer. In certain of thepreceding embodiments, the polymer or copolymer is present in the tiretread of the tire component. Furthermore, in accordance with certain ofthe preceding embodiments, the styrene monomer is polymerized with aconjugated diene-containing monomer selected from the group consistingof 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene,1,3-hexadiene, 2-methyl-1,3-pentadiene, 3,4-dimethyl-1,3-hexadiene,4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, phenyl-1,3-butadiene,and combinations thereof. In addition, in certain of the precedingembodiments, the copolymer is a styrene-butadiene-styrene (SBS) blockcopolymer or a styrene-isoprene-styrene (SIS) block copolymer.

In accordance with one or more embodiments, a tire component comprisinga rubber composition is disclosed. The rubber composition comprises from5 to 100 phr of first polymer or copolymer, from 0 to 95 phr of a secondpolymer or copolymer, and from 5 to 200 phr of at least one reinforcingfiller. The first polymer or copolymer comprises a styrene monomerderived from a biobased styrene source material and optionally at leastone conjugated diene-containing monomer. The styrene monomer contains50% to 100% modern carbon atoms. The second polymer or copolymerselected from the group consisting of polyisoprene, polybutadiene,emulsion styrene-butadiene copolymer, solution styrene-butadienecopolymer, natural rubber, and combinations thereof. Furthermore, inaccordance with certain of the preceding embodiments, the firstcopolymer contains 100% modern carbon atoms, and any of thepolyisoprene, polybutadiene, emulsion styrene-butadiene copolymer, andsolution styrene-butadiene copolymer present in the second polymer orcopolymer is 100% modern carbon atoms.

In accordance with certain of the preceding embodiments, the rubbercomposition is contained in a tread, a sidewall, or both a tread and asidewall. In accordance with certain of the preceding embodiments, therubber composition comprises from 20 to 100 phr of the first polymer orcopolymer and from 0 to 80 phr of the second copolymer. In addition, incertain of the preceding embodiments, the first polymer or copolymer ofthe rubber composition is selected from the group consisting ofstyrene-butadiene, styrene-isoprene, styrene-isoprene-butadiene, andcombinations thereof. In accordance with the preceding embodiment, therubber composition is contained in a tire tread. Furthermore, inaccordance with certain of the preceding embodiments, the biobasedstyrene source material includes at least one of cinnamic acid, aderivative of cinnamic acid, syngas, methane, ethanol, butanol, andcombinations thereof.

Furthermore, in certain of the preceding embodiments, the styrenemonomer contains 100% modern carbon atoms. Moreover, in accordance withcertain of the preceding embodiments, the first copolymer is producedfrom the styrene monomer using anionic polymerization or emulsionpolymerization. In certain of the preceding embodiments, the firstcopolymer is a styrene-butadiene copolymer containing from 10% to 60% ofbound styrene by weight of the copolymer. In accordance with certain ofthe preceding embodiments, the first copolymer is a styrene-butadienecopolymer containing from 20% to 40% of bound styrene by weight of thecopolymer. In certain of the preceding embodiments, the first copolymeris a styrene-butadiene copolymer, and up to 60% by weight of the totalstyrene in the copolymer is present in microblock form.

Furthermore, in certain of the preceding embodiments, the firstcopolymer is a styrene-butadiene copolymer produced from a 1,3-butadienemonomer derived from a biobased butadiene source material. The1,3-butadiene monomer contains 25% to 100% modern carbon atoms.

Moreover, in certain of the preceding embodiments, the first copolymeris a styrene-isoprene copolymer produced from an isoprene monomerderived from a biobased isoprene source material, wherein the isoprenemonomer contains 25% to 100% modern carbon atoms.

Furthermore, in certain of the preceding embodiments, the firstcopolymer is a styrene-isoprene-butadiene copolymer and thestyrene-isoprene-butadiene copolymer is produced from at least one of a1,3-butadiene monomer derived from a biobased butadiene source material,an isoprene monomer derived from a biobased isoprene source material,and combinations thereof. When the styrene-isoprene-butadiene copolymeris produced from a biobased butadiene source material, the 1,3-butadienemonomer contains 25% to 100% modern carbon atoms. In addition, when thestyrene-isoprene-butadiene copolymer is produced from a biobasedisoprene source material, the isoprene monomer contains 25% to 100%modern carbon atoms.

In certain of the preceding embodiments, the reinforcing filler of therubber composition is selected from the group consisting of carbonblack, silica, clay, mica, starch, magnesium hydroxide, aluminumhydroxide, zinc oxide, and combinations thereof. In addition, in certainof the preceding embodiments, the rubber composition further comprises acurative selected from the group consisting of vulcanizing agents,vulcanizing accelerators, anti-scorch agents, vulcanizing inhibitors,and combinations thereof.

In accordance with one or more embodiments, a process for producing aconjugated diene-containing copolymer is disclosed. The processcomprises providing a bioderived styrene monomer containing 50% to 100%modern carbon atoms; and polymerizing the styrene monomer in thepresence of at least one conjugated-diene monomer to form a conjugateddiene-containing copolymer. In accordance with certain of the precedingembodiments, the styrene monomer is polymerized in the presence of1,3-butadiene monomer thereby forming a styrene-butadiene copolymer. Incertain of the preceding embodiments, the styrene monomer is polymerizedin the presence of isoprene monomer thereby forming a styrene-isoprenecopolymer. Furthermore, in certain of the preceding embodiments, thestyrene is polymerized in the presence of 1,3-butadiene monomer and anisoprene monomer thereby forming a styrene-isoprene-butadiene copolymer.In addition, in certain of the preceding embodiments, the copolymer isfunctionalized at one or more of the polymer head, the polymer tail, andthe polymer backbone.

In accordance with certain of the preceding embodiments, thepolymerizing step of the process is anionic polymerization. In certainof the preceding embodiments, the anionic polymerization comprises theuse of at least one organometallic anionic initiator. In certain of thepreceding embodiments, the at least one organometallic anionic initiatoris an organic alkali metal compound. In accordance with certain of thepreceding embodiments, the at least one organometallic anionic initiatoris selected from the group consisting of organolithium, organomagnesium,organosodium, organopotassium, tri-organotin-lithium compounds, andcombinations thereof.

In accordance with certain of the preceding embodiments, thepolymerizing step of the process is emulsion polymerization. In certainof the preceding embodiments, the emulsion polymerization occurs at from0 to 10° C.

Furthermore, in accordance with certain of the preceding embodiments,the tire component comprises a rubber composition containing theconjugated diene copolymer produced by the aforementioned process. Inaccordance with certain preceding embodiments, the rubber composition iscontained in a tire tread. In addition, in certain of the precedingembodiments, the rubber composition further comprises 5 to 95 phr of asecond polymer or copolymer selected from the group consisting ofpolyisoprene, polybutadiene, emulsion styrene-butadiene copolymer,solution styrene-butadiene copolymer, natural rubber, and combinationsthereof; and 5 to 200 phr of at least one reinforcing filler. Moreover,in accordance with certain of the preceding embodiments, the rubbercomposition comprises at least a first styrene-butadiene copolymer and asecond styrene-butadiene copolymer. In accordance with the precedingembodiment, each of the first and second styrene-butadiene copolymers ispolymerized from the bioderived styrene monomer, and the percent boundstyrene in the first styrene-butadiene copolymer is different than thepercent bound styrene in the second styrene-butadiene copolymer.

EXAMPLES

The following examples illustrate specific and exemplary embodimentsand/or features of the embodiments of the present disclosure. Theexamples are provided solely for the purposes of illustration and shouldnot be construed as limitations of the present disclosure. Numerousvariations over these specific examples are possible without departingfrom the spirit and scope of the presently disclosed embodiments.

Example 1 Preparation of Biobased Styrene

In a dinitrogen atmosphere glovebox, biobased hydrocinnamic acid (1gram, 6.7 millimoles), palladium(II) chloride (3 milligram, 0.25 mole%), pivalic anhydride (1.35 milliliter, 6.7 millimoles), and phosphineligand (2.2 mole % or 4.4 mole %) are loaded into an oven-dried 15milliliter round-bottom flask equipped with a Teflon stir bar. Not allof the reagents are soluble at room temperature, resulting in aheterogeneous mixture. The round-bottom flask is attached to anoven-dried short-path distillation apparatus, then removed from theglovebox and placed under an atmosphere of dinitrogen or argon gas. Thereaction flask is lowered into a 160° C. to 170° C. oil bath and allowedto continue to heat until the oil bath reached 190° C. In most cases,the reaction mixture becomes homogenous and yellow after heating. Oncethe reaction mixture reaches about 185° C., it begins to bubblevigorously, thereby indicating loss of carbon monoxide. As the reactionproceeds for two hours, the distillate of the reaction mixture iscollected. After the two hours, heating is ceased and the reaction isexposed to air. The distillate is colorless and includes styrene,pivalic acid, and pivalic anhydride. The residual reaction mixture isyellow and contains the catalyst residue and any unreacted raw materialsnot present in the distillate.

The distillate comprising styrene (3.13 grams, 30.0 millimoles), pivalicacid (6.35 grams, 62.1 millimoles), and pivalic anhydride (0.63 grams,3.4 millimoles) is diluted with 35 milliliters of pentanes and is washedwith a 1.7 M aqueous NaOH solution (3×50 mL). The organic phase isdiluted with an additional 15 milliliters of pentanes and is dried overMgSO₄. The mixture is then filtered, and after filtration, the solventis removed thus providing a mixture of styrene and pivalic anhydride (ascharacterized by ¹H NMR spectroscopy) that is then chromatographed(column diameter of 5 centimeter, and column height of 25 centimeter) onsilica using pentane as the eluent to yield biobased styrene (2.03grams, 65%).

Example 2 Anionic Polymerization of Styrene-Butadiene Copolymer

To a dinitrogen purged and capped bottle is added 360 grams of hexane,12 grams of biobased styrene and 28 grams of 1,3-butadiene. The biobasedstyrene is prepared in the manner described above in Example 1 of thisdisclosure. Then, 0.24 milliliters of 1.65 M BuLi (0.4 millimoles) isadded with 0.12 millimoles 2,2-ditetrahydrofurylpropane. The bottle isplaced in a 50° C. bath for 4 hours. After the 4 hours elapses, 1milliliter of isopropanol (IPA) is added to quench the reaction and thebottle contents are discharged into a mixture of IPA and2,6-di-tert-butyl-4-methylphenol (BHT). The resultant styrene-butadienecopolymer has a 5% to 60% modern carbon atom content as measured by ASTMD6866.

Example 3 Emulsion Polymerization of Styrene-Butadiene Copolymer

To a dinitrogen purged and capped bottle is added 180 grams of distilledwater, 5 grams of sodium stearate, 25 grams of biobased styrene, 75grams of 1,3-butadiene, 0.2 grams of dodecylmercaptan, 0.017 g of iron(II) sulfate, 0.06 g of ethylenediamine tetraacetic acid (EDTA), and0.17 grams of cumene hydroperoxide. The biobased styrene is prepared inthe manner described above in Example 1 of this disclosure. The bottleis placed in a 5° C. bath for 12 hours. Then, 0.4 grams of a 1M BHTsolution in hexanes is added and the solution is discharged into a 1 Msulfuric acid solution. The resultant styrene-butadiene copolymer has a5% to 60% modern carbon atom content as measured by ASTM D6866.

Example 4 Anionic Polymerization of Styrene-Butadiene Copolymer (UsingBiobased Styrene Monomer and Biobased 1,3-Butadiene Monomer)

A styrene-butadiene copolymer is made according to the process providedin Example 2 except that both the styrene monomer and the 1,3-butadienemonomer are biobased. The biobased styrene is prepared in the mannerdescribed above in Example 1 of this disclosure. The biobased1,3-butadiene monomer is prepared from biobased ethanol in accordancewith the process described in Toussaint, W. J. et al., “Production ofButadiene from Alcohol,” Ind. Eng. Chem., 1947, 39 (2), pages 120-125.The resultant styrene-butadiene copolymer has a 25% to 100% moderncarbon atom content as measured by ASTM D6866.

Example 5 Emulsion Polymerization of Styrene-Butadiene Copolymer (UsingBiobased Styrene Monomer and Biobased 1,3-Butadiene Monomer)

A styrene-butadiene copolymer is made according to the process providedin Example 3 except that both the styrene monomer and the 1,3-butadienemonomer are biobased. The biobased styrene is prepared in the mannerdescribed above in Example 1 of this disclosure. The biobased1,3-butadiene monomer is prepared from biobased ethanol in accordancewith the process described in Toussaint, W. J. et al., “Production ofButadiene from Alcohol,” Ind. Eng. Chem., 1947, 39 (2), pp. 120-125. Theresultant styrene-butadiene copolymer has a 25% to 100% modern carbonatom content as measured by ASTM D6866.

Example 6 Anionic Polymerization of Styrene-Isoprene-Butadiene Copolymer

A monomer solution in hexane containing 20% by weight of biobasedstyrene, 40% by weight 1,3-butadiene, and 40% by weight isoprene isdried in a column packed with silica, alumina, a molecular sieve, andsodium hydroxide resulting in a monomer solution in hexane having 18.4%by weight solids. The biobased styrene is prepared in the mannerdescribed above in Example 1 of this disclosure. The resulting monomersolution is charged in a dinitrogen purged and sealed 3.8 liter reactor.Then, 3.07 milliliter of a potassium p-amylate solution (0.68 M inhexane) and 2 milliliter of n-butyllithium (1.04 M in hexane) is chargedinto the reactor. The reactor is maintained at a temperature of 50° C.with agitation for 7-8 hours, after which 2 milliliter of methyl alcoholis added to quench the reaction and form a styrene-isoprene-butadienecopolymer cement. Then, 1 phr of an antioxidant is added to theresulting cement. The hexane is evaporated in a vacuum oven at 50° C.overnight. The resulting styrene-butadiene-isoprene copolymer has 18%bound styrene units, 16% bound 1,2-butadiene units, 24% bound1,4-butadiene units, 18% bound 3,4-polyisoprene units, 24% bound1,4-polyisoprene units, and 2% bound 1,2-isoprene units. The resultantstyrene-isoprene-butadiene copolymer has a 5% to 60% modern carbon atomcontent as measured by ASTM D6866.

Example 7 Production of Biobased Styrene-Butadiene Copolymer

A quantity of biobased styrene (97% modern carbon) was provided. Thestyrene was described as having been produced from biobasedhydrocinnamic acid. This biobased styrene was utilized to preparesamples of styrene-butadiene copolymer (SBR), according to theprocedures described below in 7B and 7C. A control sample of SBR usingnon-biobased (i.e., fossil fuel derived) styrene was prepared accordingto the procedures described below in 7A. The samples according to 7A, 7Band 7C were produced using non-biobased (i.e., fossil fuel derived)1,3-butadiene. Once produced, the SBRs were subjected to variousanalysis. Results appear in Table 1 below. Percent biobased carbonanalysis was performed upon the SBR samples using ASTM D6866-12. Thevalues disclosed for Mn and Mw were determined using GPC. The GPCmeasurements disclosed herein are calibrated with polystyrene standardsand Mark-Houwink constants. The microstructure content disclosed herein(i.e., vinyl-contents (%)) were determined by FTIR, i.e., the sampleswere dissolved in CS2 and subjected to FTIR.

Sample 7A: Synthesis of SBR Using Fossil Fuel Derived Styrene andButadiene.

To a 0.8 liter dry, nitrogen purged, capped bottle was added 207.1 gramsof anhydrous hexanes, 18.3 grams of 32.6 weight percent fossil fuelderived styrene in hexanes, and 178.9 grams of 19.0 weight percent1,3-butadiene in hexanes. Then, 0.13 milliliter of 1.6 M n-butyl lithium(n-BuLi) in hexanes and 0.08 milliliter of 1.6 M2,2-ditetrahydrofurylpropane (DTHFP) in hexanes were added and thebottle agitated in a 50° C. water bath. After 4 hrs, 0.1 milliters ofisopropanol was added to the bottle. The polymer was coagulated inisopropanol containing antioxidant and drum dried to yield a polymerhaving the properties listed in Table 1.

Sample 7B: Synthesis of Non-Functionalized SBR Using Biobased Styrene.

To a 0.8 liter dry, nitrogen purged, capped bottle was added 207.1 gramsof anhydrous hexanes, 18.3 grams of 32.7 weight percent biobased styrene(97% modern carbon) in hexanes, and 178.9 grams of 19.0 weight percent1,3-butadiene in hexanes. Then, 0.25 milliliters of 1.6 M n-BuLi inhexanes and 0.08 milliliters of 1.6 M 2,2-ditetrahydrofurylpropane(DTHFP) in hexanes were added and the bottle agitated in a 50° C. waterbath. After 4 hrs, 0.1 milliliters of isopropanol was added to thebottle. The polymer was coagulated in isopropanol containing antioxidantand drum dried to yield a polymer having the properties listed in Table1

Sample 7C: Synthesis of Functionalized SBR Using Biobased Styrene.

To a 0.8 liter dry, nitrogen purged, capped bottle was added 215.9 gramsof anhydrous hexanes, 36.7 grams of 32.7 weight percent biobased styrene(97% modern carbon) in hexanes, and 147.4 grams of 19.0 weight percent1,3-butadiene in hexanes. Then, 0.25 milliliters of 1.6 M n-BuLi inhexanes and 0.08 milliliters of 1.6 M 2,2-ditetrahydrofurylpropane(DTHFP) and 0.13 milliliters of 2.78 M hexamethyleneimine in cyclohexanewere added and the bottle agitated in a 50° C. water bath. After 4 hrs,the 0.1 milliliters of 0.25 M tin tetrachloride was added to the bottle.Thereafter, isopropanol was added to the bottle. The polymer wascoagulated in isopropanol containing antioxidant and drum dried to yielda polymer with properties listed in Table 1.

TABLE 1 Analysis of SBR Example A B C M_(n) (kg/mol) 252.7 208 98 M_(w)(kg/mol) 267.7 284 151 % Coupling 0 0 38 % Vinyl (BD = 100%) 62 65.155.2 Weight Percent Styrene 14.2 14.9 29.5 Tg, ° C. −32.8 −26.9 −22.8 %Biobased Carbon in 0 12 26 Copolymer

Example 8 Preparation of Rubber Compositions

The SBRs prepared in Examples 7A, 7B and 7C were utilized to preparerubber compositions according to the formulas provided in Tables 2-4,below. Each rubber compound was prepared in three stages named initial,remill and final. In the initial part, the SBR from examples 7A, 7B or7C was mixed with silica, an antioxidant, stearic acid, and aromaticoil.

The initial portion of the compound was mixed in a 65 gram Banbury mixeroperating at 60 RPM and 133° C. First, polymer was placed in the mixer,and after 0.5 minutes, the remaining ingredients except the stearic acidwere added. The stearic acid was then added after 3 minutes. Theseinitials were mixed for 5-6 minutes. At the end of mixing thetemperature was approximately 165° C. The sample was transferred to amill operating at a temperature of 60° C., where it was sheeted andsubsequently cooled to room temperature.

TABLE 2 Initial Formulation Ingredient Example 8A (Control)* Example 8B*Example 8C* Sample A 60 0 0 Sample B 0 60 0 Sample C 0 0 60 NaturalRubber 40 40 40 Silica 52.5 52.5 52.5 Oil 10 10 10 Aromatic Oil 2 2 2Stearic Acid 2 2 2 Antiozonant 0.95 0.95 0.95 Total 167.45 167.45 167.45

TABLE 3 Remill Formulation Ingredient Example 8A-8C Appropriate Initial167.45 Silica 5 Silane Shielding Agent¹ 2.5 Total 174.95¹(bis(triethoxysilylpropyl)disulfide)

TABLE 4 Final Formulation Ingredient Example 8A-8C Appropriate Remill174.95 Sulfur 1.5 Accelerators 4.1 Zinc Oxide 2.5 Total 183.05

The remill was mixed by adding the initial ingredients and silaneshielding agent to the mixer simultaneously. The initial mixertemperature was 95° C. and it was operating at 60 RPM. The finalmaterial was removed from the mixer after three minutes when thematerial temperature was 145° C. The sample was transferred to a milloperating at a temperature of 60° C., where it was sheeted andsubsequently cooled to room temperature.

The final ingredients were mixed by adding the remill and the curativematerials to the mixer simultaneously. The initial mixer temperature was65° C. and it was operating at 60 RPM. The final material was removedfrom the mixer after 2.5 minutes when the material temperature wasbetween 90-95° C. The finals were sheeted into Dynastat buttons and6×6×0.075 inch sheets. The samples were cured at 171° C. for 15 minutesin standard molds placed in a hot press.

After preparation of the rubber compositions, various viscoelasticproperties were measured. These measurements were performed according tothe procedures described below. Results are reported in Table 5 below.

TABLE 5 Property Example 8A Example 8B Example 8C ML1 + 4 (130° C.) 58.625.6 66.1 200% Modulus @23° C. (MPa) 7.997 8.507 7.619 T_(b) @23° C.(MPa) 14.518 19.382 22.403 E_(b) @23° C. (%) 270.483 300.132 333.981 tanδ 5% E, 60° C. 0.123 0.120 0.173 ΔG′ (50° C.) (MPa)* 3.51 2.75 3.89 tanδ 0.5% E, 0° C. 0.309 0.340 0.630 % Biobased Carbon 36 43 49 *ΔG′ =G′(0.25% E) − G′(14.5% E) ¹the presence of natural rubber contributes tothe biobased carbon

The Mooney viscosities disclosed herein were determined at 130° C. usingan Alpha Technologies Mooney viscometer with a large rotor, a one minutewarm-up time, and a four minute running time. More specifically, theMooney viscosity was measured by preheating a sample from each batch to130° C. for one minute before the rotor starts. The Mooney viscosity wasrecorded for each sample as the torque at four minutes after the rotorstarted.

G′ was measured by a strain sweep conducted with an Advanced RheometricExpansion System (ARES) from TA Instruments. The test specimen has acylindrical button geometry having a diameter of 9.27 mm and a 15.6 mmlength. The test is conducted using a frequency of 15 Hz. Thetemperature is held constant at the desired temperature, 50° C. Thestrain was swept from 0.25% to 14.75%. ΔG′ represents G′(0.25% E)-G′(14.5% E).

Tan δ was measured using a dynamic compression test done with aDynastat™ mechanical spectrometer (Dynastatics Instruments Corp.;Albany, N.Y.) using a cylindrical test specimen (9.27 mm diameter×15.6mm height). The temperature is held constant at the desired temperature,50° C. The sample is compressed under a static load of 2 kg beforetesting. After it reached an equilibrium state, the test started with adynamic compression load of 1.25 kg at a frequency of 15 Hz.

Tensile mechanical properties were determined following the guidelines,but not restricted to, the standard procedure described in ASTM-D412,using ring samples with a dimension of 1.27 mm in width and 1.91 mm inthickness. A specific gauge length of 25.4 mm was used for the tensiletest. Specimens are strained at a constant rate and the resulting forceis recorded as a function of extension (strain). Force readings areexpressed as engineering stresses by reference to the originalcross-sectional area of the test piece. The specimens are tested at 23°C. Breaking strength/tensile strength (Tb), elongation atbreak/elongation performance (Eb), Tb×Eb and modulus at 23° C. are alsoreported.

Notably, the viscosity (ML 1+4) of the SBR according to Example 7 waslower than the viscosity of the control SBR according to Example 6(about 26 as compared to about 59). Without being bound by any theory,the lower viscosity may be due to a combination of higher Mw/Mn inExample 7 and the presence of a quantity of lower molecular weightmaterial in the SBR of Example 7. The measurement of tan δ at 60° C. iscommonly understood to provide an indication of a compound's rollingresistance (i.e., if incorporated into a tire tread) and the measurementof tan δ at 0° C. is commonly understood to provide an indication of acompound's wet traction (i.e., if incorporated into a tire tread).Generally, a polymer with a higher Tg will tend to provide a rubbercomposition with an increase in both tan δ values (i.e., an increase inthe rolling resistance and an increase in wet traction). Increasing bothof these (or decreasing both), especially in a tire tread, is generallyundesirable as tire manufacturers usually seek to decrease rollingresistance and increase wet fraction. As can be seen from an examinationof the data in Table 5, the rubber composition according to Example 7has an increase in wet traction (i.e., 0.340 versus 0.309), but also hasa decrease in rolling resistance (i.e., 0.120 versus 0.123).

As to the rubber composition according to Example 8, it utilizes afunctionalized SBR made from the bio styrene monomer; while the rubbercomposition according to Example 8 shows an increase in wet traction ascompared to the non-functionalized control in Example 6 (i.e., 0.630versus 0.309) that is unexpected since generally the use of afunctionalized SBR would be expected to decrease the wet fraction.Furthermore, with respect to Example 8, while there is an increase inrolling resistance (i.e., 0.173 versus 0.123), that increase is not assignificant as would ordinarily be expected with the extent of theincrease in wet traction. (The wet traction increases more than 100% ascompared to Example 6 whereas the increase in rolling resistance isabout 40%.)

Accordingly, from an examination of the viscoelastic properties providedin Table 5, it appears that the incorporation of biobased styrene into aSBR and subsequent use of that SBR in a rubber composition may allow foran improved balancing of viscoelastic properties in the rubbercomposition, more specifically an increase in wet fraction without acorresponding increase in rolling resistance, and in certain instancesan increase in wet traction accompanied by a decrease in rollingresistance.

Example 9 Analysis of Biobased Styrene Monomer

A sample of biobased styrene monomer containing 97% modern carbon, anddescribed as having been produced from biobased hydrocinnamic acid, wasanalyzed for styrene monomer and impurities using GC-MS. According tothe analysis, the monomer sample contained 98.8% styrene monomer andalso contained certain styrene-based impurities. Fossil-fuel basedstyrene monomer sources are known to contain 99.8% styrene monomer, and,therefore, no more than 0.2% styrene-based impurities. Thestyrene-derived impurities identified in the biobased styrene monomercomprised styrene dimers, styrene trimers, and hydroxy-substitutedstyrene compounds. More specifically, the styrene-derived impuritieswere identified (using a standard library) as including ethylbenzene,1-phenyl-ethanol, styrene dimer, styrene trimer,bis(1-phenyl-ethyl)ether, and 1,3-diphenyl-3-hydroxy-1-butene.

As used in the description of the invention and the appended claims, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

To the extent that the term “includes” or “including” is used in thespecification or the claims, it is intended to be inclusive in a mannersimilar to the term “comprising” as that term is interpreted whenemployed as a transitional word in a claim. Furthermore, to the extentthat the term “or” is employed (e.g., A or B) it is intended to mean “Aor B or both.” When the applicants intend to indicate “only A or B butnot both” then the term “only A or B but not both” will be employed.Thus, use of the term “or” herein is the inclusive, and not theexclusive use. See Bryanl A. Garner, A Dictionary of Modern Legal Usage624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into”are used in the specification or the claims, it is intended toadditionally mean “on” or “onto.” Furthermore, to the extent the term“connect” is used in the specification or claims, it is intended to meannot only “directly connected to,” but also “indirectly connected to”such as connected through another component or components.

Unless otherwise indicated herein, all sub-embodiments and optionalembodiments are respective sub-embodiments and optional embodiments toall embodiments described herein. While the present application has beenillustrated by the description of embodiments thereof, and while theembodiments have been described in considerable detail, it is not theintention of the applicants to restrict or in any way limit the scope ofthe appended claims to such detail. Additional advantages andmodifications will readily appear to those skilled in the art.Therefore, the application, in its broader aspects, is not limited tothe specific details, the representative apparatus, and illustrativeexamples shown and described. Accordingly, departures may be made fromsuch details without departing from the spirit or scope of theapplicant's general inventive concept.

What is claimed is:
 1. A method for increasing the wet traction of arubber composition, the method comprising incorporating 5-100 phr of atleast one polymer or copolymer containing a styrene monomer with 50% to100% modern carbon atoms into the rubber composition, wherein either: a.wet traction is increased by about 10% or more while maintaining ordecreasing rolling resistance as compared to a control rubbercomposition that replaces the modern carbon-containing polymer orcopolymer with a polymer or copolymer containing no modern carbon atoms;or b. wet traction is increased by more than 50% and rolling resistanceis increased by less than 50% as compared to a control rubbercomposition that replaces the modern carbon-containing polymer orcopolymer with a polymer or copolymer containing no modern carbon atoms.2. The method of claim 1, wherein the at least one polymer or copolymercontaining a styrene monomer with 50 to 100% modern carbon atoms isfunctionalized.
 3. The method of claim 2, wherein the functionalizationis at one or more of the head, the tail, or the polymer backbone.
 4. Themethod of claim 2, wherein the functionalization is by coupling.
 5. Themethod of claim 2, wherein the balancing comprises (a) and the wettraction increases by at least 10% as compared to a control rubbercomposition that replaces the modern carbon-containing polymer orcopolymer with a polymer or copolymer containing no modern carbon atoms.6. The method of claim 1, wherein the at least one polymer or copolymercontaining a styrene monomer with 50% to 100% modern carbon atoms ispresent in the rubber composition in an amount of 50-100 phr.
 7. Themethod of claim 1, wherein the styrene monomer contains at least 0.5% byweight styrene-derived impurities.
 8. The method according to claim 7,wherein the styrene-derived impurities comprise styrene dimers, styrenetrimers, and hydroxy-substituted styrene compounds.
 9. The methodaccording claim 1, wherein the styrene monomer is produced from cinnamicacid or a derivative thereof.
 10. The method according to claim 1,wherein the at least one polymer or copolymer containing a styrenemonomer with 50% to 100% modern carbon atoms comprises astyrene-butadiene copolymer.
 11. The method according to claim 1,wherein the rubber composition further comprises up to 95 phr of atleast one additional polymer or copolymer selected from the groupconsisting of polyisoprene, polybutadiene, emulsion styrene-butadienecopolymer, solution styrene-butadiene copolymer, natural rubber, andcombinations thereof.
 12. The method according to claim 1, wherein therubber composition further comprises 5 to 200 phr of at least onereinforcing filler.
 13. A method for increasing the wet traction of arubber composition, the method comprising incorporating: a. 5-100 phr ofat least one polymer or copolymer containing a styrene monomer with 50%to 100% modern carbon atoms; b. 0-95 phr of at least one additionalpolymer or copolymer selected from the group consisting of polyisoprene,polybutadiene, emulsion styrene-butadiene copolymer, solutionstyrene-butadiene copolymer, natural rubber, and combinations thereof;and c. 5-200 phr of at least one reinforcing filler to form the rubbercomposition, wherein either: d. wet traction is increased by about 10%or more while maintaining or decreasing rolling resistance as comparedto a control rubber composition that replaces the moderncarbon-containing polymer or copolymer with a polymer or copolymercontaining no modern carbon atoms; or e. wet traction is increased bymore than 50% and rolling resistance is increased by less than 50% ascompared to a control rubber composition that replaces the moderncarbon-containing polymer or copolymer with a polymer or copolymercontaining no modern carbon atoms.
 14. The method of claim 13, whereinthe at least one polymer or copolymer containing a styrene monomer with50 to 100% modern carbon atoms is functionalized.
 15. The method ofclaim 13, wherein the balancing comprises (d) and the wet tractionincreases by at least 10% as compared to a control rubber compositionthat replaces the modern carbon-containing polymer or copolymer with apolymer or copolymer containing no modern carbon atoms.
 16. The methodof claim 13, wherein the at least one polymer or copolymer containing astyrene monomer with 50% to 100% modern carbon atoms is present in therubber composition in an amount of 50-100 phr.
 17. The method accordingto claim 13, wherein the at least one polymer or copolymer containing astyrene monomer with 50% to 100% modern carbon atoms comprises astyrene-butadiene copolymer.
 18. A rubber composition having increasedwet traction comprising a. 5-100 phr of at least one polymer orcopolymer containing a styrene monomer with 50% to 100% modern carbonatoms, b. 0 to 95 phr of at least one additional polymer or copolymerselected from the group consisting of polyisoprene, polybutadiene,emulsion styrene-butadiene copolymer, solution styrene-butadienecopolymer, natural rubber, and combinations thereof; and c. 5 to 200 phrof at least one reinforcing filler, wherein the increased wet tractioncomprises either: d. increasing wet traction by about 10% or more whilemaintaining or decreasing rolling resistance as compared to a controlrubber composition that replaces the modern carbon-containing polymer orcopolymer with a polymer or copolymer containing no modern carbon atoms;or e. increasing wet traction by more than 50% and increasing rollingresistance by less than 50% as compared to a control rubber compositionthat replaces the modern carbon-containing polymer or copolymer with apolymer or copolymer containing no modern carbon atoms.
 19. The rubbercomposition of claim 18, wherein the at least one polymer or copolymercontaining a styrene monomer with 50% to 100% modern carbon atomscomprises a styrene-butadiene copolymer.
 20. The rubber composition ofclaim 18, wherein the at least one polymer or copolymer containing astyrene monomer with 50% to 100% modern carbon atoms is present in therubber composition in an amount of 50-100 phr.
 21. The rubbercomposition of claim 18, wherein the at least one polymer or copolymercontaining a styrene monomer with 50% to 100% modern carbon atomscomprises a block copolymer selected from styrene-butadiene-styrene andstyrene-isoprene-styrene.
 22. The rubber composition of claim 19,wherein the styrene-butadiene copolymer comprises 10-60% bound styrene.